The observation of a constant rupture velocity similar to Culick's law, even at high \(\phi \) , suggests that the non-Newtonian rheology has a minimal effect on film rupture dynamics. Therefore, it is possible that the rupture of colloidal films may still be modeled as that of a Newtonian fluid. The well-known picture of Newtonian film rupture is that the rim at the rupture boundary collects more and more fluid as it rolls outward. In other words, the information of rupture travels at the same speed as the expanding circular rim, and does not affect most of the film outside the rupture, except for a small region around the rupture rim, referred to as an aureole [1]}. Thus, it is expected that no shear is experienced by the film outside of the aureole. Therefore, our observation that the non-Newtonian rheology has a minimal effect on the rupture, even at high values of \(\phi \) , is consistent with this mechanism. In addition to introducing non-Newtonian flow behavior, adding colloidal fluids of colloidal particles increases the effective viscosity of the fluid [2]}, [3]} even in the zero-shear limit. To compare the rupture of colloidal films to its Newtonian counterpart, we used the zero-shear viscosity of suspensions measured via cone-plate rheology. We note that there are several models for predicting suspension viscosity in this limit, and using one of these models instead of experimental viscosity measurements does not alter our conclusions (see SI for more details).
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